Semiconductor devices, to be useful, must be electrically connected to one another or to other electronic devices or to interconnect boards such as printed circuit boards and carrier boards. Leadframes made from conductive metal such as copper, silver or gold are often used to electrically connect the semiconductor device to other electronic devices. One popular and flexible method of connecting semiconductors devices to leadframes and/or other electronics is wire bonding. Bondwires usually consist of aluminum, copper or gold. Bond wire diameters typically range from about 15 μm to several hundred micrometers in high-power applications. There are two basic types of wire bonding—ball bonding and wedge bonding.
Ball bonding usually uses a combination of heat, pressure and ultrasonic energy. In ball bonding, a small molten ball is formed at the end of the bondwire by application of a high voltage charge through a tool holding and dispensing the wire known as a capillary. This ball is placed in contact with the electrical contact surface of a chip that is usually copper or aluminum. A combination of heat, pressure and ultrasonic energy is then applied which creates a weld between the ball and the metal surface that it contacts. The ball bond is sometimes referred to as the first bond because it is usually the first bond made in wire bonding of an IC chip/die to a leadframe.
In a die leadframe interconnection, the type of wire bond that is generally used to connect the second end of the bond wire to the leadframe is a called a wedge bond or sometimes second bond. It is formed by crushing the end of the bondwire between the leadframe or other metal surface and the tip of the capillary tool.
A leadframe often forms part of the electrical connection between a semiconductor device and other electronics. In some cases the die and bond wires connecting it to a leadframe are encapsulated within a hard protective shell that is typically formed by a molding operation. One or more surfaces of lead portions of the leadframe are not covered by the protective shell and may be electrically and mechanically connected to external circuits. The combination of an integrated circuit (“IC”) die, leadframe, bond wires and encapsulating material is generally referred to as an integrated circuit package (IC package). There are various types of IC packages. The difference between IC packages is primarily determined by how the lead portions of the leadframe are exposed, the configuration and number of the exposed lead portions, how the package is mounted and the size or shape of the package. For example below is a list of so called “flat packages” that are commercially available:                Flatpack, early metal/ceramic case with flat leads        CFP: Ceramic Flat Pack        CQFP: ceramic quad flat-pack, similar to PQFP        BQFP: Bumpered Quad Flat Pack        DFN: Dual Flat Pack, No Lead        
ETQFP: Exposed Thin Quad Flat Package
PQFN: power quad flat-pack, no-leads, with exposed die-pad[s] for heatsinking                PQFP: Plastic quad flat package        LQFP: Low-profile Quad Flat Package        QFN: Quad Flat No Leads, also called micro lead frame (MLF).        Quad Flat Package: (QFP)        MQFP—Metric Quad Flat Pack, a QFP with metric pin distribution        HVQFN: Heat-sink very-thin quad flat-pack no-leads        SIDEBRAZE        TQFP: Thin Quad Flat Pack        TQFN: Thin Quad Flat No-Lead        VQFB: Very-thin Quad Flat Pack        
Even though IC packages are available in an assortment of types and sizes, certain features thereof such as, for example, wire bond connections between an IC die and a leadframe, have remained essentially the same from package to package.